Miniature sampler using in situ extraction and analysis

Abstract

A novel, inexpensive passive sampler consisting of a small vial with a glass insert containing a carbonaceous sorbent and sealed with an open top screw cap containing a glass fibre draft shield was designed. The analytical method allowed in situ extraction (carbon disulfide) and manual or automated withdrawal of an extract aliquot directly from the sampler for determination of airborne organics. Method detection limits better than 2 mg/m³ ‐ h were found both in controlled exposures to five hydrocarbons and with selected chlorinated and simple hydrocarbons in seven day field exposures. Triplicate determinations showed a precision better than 7% RSD for two and eight hour exposures to propylbenzene, decane, butylbenzene, tridecane and octylbenzene at 2 mg/m³ under controlled conditions. The sampling rates determined experimentally for eight hour exposures were 19 to 43 % higher than those estimated from sampler dimensions and diffusion coefficients for the first four compounds. Probably due to incomplete va‐porization of octylbenzene, its experimental sampling rate was about 65% of the estimated value. The feasibility of the method was supported by concurrent field measurements obtained with the miniature sampler and the 3M OVM 3500 badge. The same chlorinated and simplehy‐drocarbons at ug/m³ levels were detected by both methods.

Key words:

• Sampler
• passive
• VOCs
• airborne
• analysis